[Clayart] Soda kiln disaster - I did use castable in comb chambers

[Helen Stone]

Dear Hand,
I actually did use homemade castable for both combustion chambers I put it
on the floor of those chambers and going upward on one side of each of the
two bag walls, also going upward on the vertical wall , left and right, of
the kiln, for about 7 inches.  What happened in that cone 11 firing was
that the floor castable held very nicely, but the wall castable sheared
away from bag walls and kiln side walls.  No wall bricks were damaged
however.  I spent a few hours hammering the castable and the soda out.  I
took pictures of the soda mix materials, the golf ball sized nuggets, all
melted like turquoise slag on the bottom of the combustion chambers,
clearly not volatilized.  So, back to square one.  Someone wrote me
personally to say that, for their soda only kiln, they are able to achieve
orange peel surface effects on the clay by spraying soda in the last hour
of the firing, and by NOT downfiring, i.e. they shut off the kiln
immediately, guess that they crash cool it possibly, which would make for
glassy surfaces .  Any thoughts, anyone?  Especially on how to adhere
skinny slices of hardbrick to the existing softbrick interiior walls and
arch...  Does anyone else get orange peel by spraying SODA , not salt, at
high temperature and shutting down immediately afterwards?

Helen in Ecuador, on Rio Yambala
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.clayartworld.com/pipermail/clayart/attachments/20180506/06c364e1/attachment.html>